Degree of challenges in AWE material properties development. Modified from ref. 225. Abbreviations: E: easy; M: moderate; D: difficult L: low; M: moderate; H: high.

AWE component: AWE material properties	Degree of challenges	Degree of improvement
Catalyst: high catalyst surface area > 50 m2 g−1	E	M
Catalyst: high catalyst utilisation > 80%	M	M
Catalyst: improved kinetics for both OER and HER with novel nickel-based alloys	M	H
Catalyst: mitigate catalyst poisoning/deactivation by foreign elements from electrolyte, and components present in the system	M	M
Catalyst: design, create, and integrate forms of recombination catalysts for gas permeation (crossover)	M	M
Catalyst: mitigate critical degradation of catalysts on the anode side to avoid loss of surface area	D	H
Catalyst: mitigate nickel hydride (NiH) formation on the cathode side	D	L
Catalyst layer: eliminate mechanical degradation of catalyst layers (delamination, dissolution)	D	H
Catalyst layer/porous transport layer: identify and reduce interface resistances from catalyst layer to PTLs	D	H
Diaphragm: identify stable polymer chemistry that can be used as ionomer (OH− transport) to be used to fabricate electrodes for alkaline electrolysers	D	H